Standard maintenance in power generators includes periodic testing of a generator's liquid cooled stator bar system for potential leaks. Typically, such testing is done using Hydraulic Integrity Test (“HIT”) Skids. One of the tests performed with a HIT Skid is the Pressure Decay Test, which measures the pressure drop over time for a potentially leaking liquid cooled stator bar system. Currently, the Pressure-Decay Tests are performed over a 24 hour period, with hourly readings recorded manually. The manually recorded data points include internal generator pressure, atmospheric pressure, and multiple temperature readings. Other data collected during such testing includes volume measurements, which are often inaccurate because they do not account for the HIT Skid's internal plumbing, pressure tanks, valves and inter-connecting plumbing between the HIT Skid and generator. This testing inaccuracy directly affects the Pressure Decay Rate calculated from the Pressure Decay Test.
This testing inaccuracy also directly affects the calculated Vacuum Decay Rate that is measured in connection with a Vacuum Decay Test also performed by the HIT Skid for the purpose of locating potential leaks in a generator's liquid cooled stator bar system. Some of the difficulties with the Vacuum Decay Test are the requirement that a technician remain near the generator to record readings every 5 minutes for 75 minutes. The data in this test, like the Pressure-Decay Test, is manually recorded, which has inherent error. In addition, the sensor used with the Vacuum Decay Test is located on the HIT Skid, which is about 25 feet from the generator, adding to the potential error of the test. Once the manual data is collected, a post-process analysis is performed to determine the Pressure Decay Rate and the Vacuum Decay Rate to ascertain whether there is a leak in a liquid cooled stator bar system of the generator under test.